The present invention relates to a universal joint and, more particularly, to a universal joint allowing operation through a larger pivotal angle and capable of withstanding high torque.
U.S. Pat. No. 4,065,941 discloses a universal joint including a tubular housing and a first ball joint having an input shaft. A ball member is disposed at an end of the input shaft and pivotably received in the housing. An attaching head having square cross sections is disposed at the other end of the input shaft and can be engaged with an impact wrench and the like. The first ball joint can pivot relative to the tubular housing until it abuts the fust end of the housing. The maximum pivotal travel of the first ball joint in the tubular housing is approximately 60°, which is still too small for use in limited spaces. A second ball joint is provided to a second end of the housing to compensate for the limited pivotal travel of the first ball joint. However, the resultant universal joint is liable to shake or vibrate, causing damage to the universal joint. Furthermore, the diameter of the input shaft is smaller than the width between two opposite sides of the attaching head, such that the input shaft is liable to deform or even break when subjected to large-torque rotation.
Thus, a need exists for a novel universal joint that allows operation through a larger pivotal angle while withstanding high torque during operation.